In a silver halide photographic element, a color image is formed when the material is exposed to light and then subjected to color development with a primary amine developer. The color development results in imagewise reduction of silver halide and production of oxidized developer. The oxidized primary anline developer subsequently reacts with one or more incorporated dye-forming couplers to form dye in an imagewise fashion. Some couplers, referred to as DIR couplers, release a development inhibitor compound or fragment upon coupling with the oxidized primary amine developer. Further, some of these DIR couplers release the inhibitor compound or fragment with a time delay. These are sometimes referred to as DIAR couplers.
A variety of magenta dye-forming coupler types have been used in color photographic materials. 2-Equivalent pyrazolone magenta dye forming couplers are known. Couplers are 2-equivalent where they require a total of 2 moles of silver to be developed to produce 1 mole of dye. Such couplers are advantageous over similar 4-equivalent couplers in that more dye is produced from the same amount of developed silver.
However, unreacted coupler typically remains following exposure and processing of a photographic element, in any area of the element which did not receive sufficient green light exposure to cause all of a magenta coupler to react with oxidized developer. Such unreacted coupler can react to cause color changes in the processed element over time. Such changes are particularly noticeable in areas which received little or no green light exposure since the processed element in those areas, would have little or no magenta dye. In the case of pyrazolone couplers, the problems in areas of little or no green light exposure, include a tendency to yellow upon exposure of the processed element to light ("printout" problem), and a tendency to form a pink stain over time particularly due to exposure of the processed element to heat ("thermal discoloration" sometimes referenced as "pinking").
Stabilizers are classes of compounds which reduce the image dye performance problem. Such stabilizers include phenols, bis-phenols, blocked phenols, blocked bis-phenols, metal and other organic complexes and other compounds, all of which have been described for use in conjunction with various color couplers. Photographic elements containing color coupler and stabilizer combinations are described, for example, in EP 0 298 321; EP 0 231 832; EP 0 161 577; EP 0 218 266; U.S. Pat. Nos. 3,043,697; 3,700,455; Kokai JP 62043-641, JP 01137-258, JP 01144-048; U.S. Pat. Nos. 4,782,011 and 4,748,100.
It would be desirable then, to provide a photographic element with a 2-equivalent pyrazolone magenta dye forming coupler, but in which printout and/or thermal discoloration problems are relatively low.